In his inaugural address at Freiburg University in 1929, Heidegger explicitly challenged the central place given to logical principles in neo-Kantianism, on the basis of a radical account of 'the nothing'. Two years later, Carnap used the tools of symbolic logic to show how Heidegger's assertions about the nothing were illogical and thus meaningless, like much of traditional metaphysics. With Anglo-American philosophers today increasingly interested in the methodology and history of the analytic tradition, it is appropriate that increasing attention is being paid to this emblematic confrontation between Carnap and Heidegger and the philosophical issues emerging from it. Among Heidegger scholars in particular, a fascinating debate has arisen about whether Heidegger's opposition to the methods of modern symbolic logic went as far as Carnap and those following him have claimed.

Greg Shirley's Heidegger and Logic aims to take this debate to the next level, in large part by providing the first sustained treatment of the relevant aspects of Heidegger's early philosophy. Shirley traces Heidegger's treatment of logical issues back to his very earliest work and its neo-Kantian context. He provides a sophisticated interpretation of Heidegger's account of the copula, truth, negation and the nothing in the period surrounding Being and Time. He also gives a detailed interpretation of Heidegger's lecture course on 'The Metaphysical Foundations of Logic', showing that for Heidegger the normativity of formal inference is grounded in the for-the-sake-of structure of the world.

In the final chapter, Shirley directly takes on the issue of the contemporary relevance of Heidegger's views. He argues that the early Heidegger's account of judgement and the foundations of inference is not rendered obsolete by post-Fregean developments in symbolic logic. Furthermore, he argues that this account enables Heidegger to fend off the charge that he is an irrationalist opponent of modern logic.